Energy of interaction in colloids and its implications in rheological modeling

Quemada, D.; Berli, Claudio Luis Alberto

doi:10.1016/s0001-8686(01)00093-8

Cited by 267 publications

(248 citation statements)

References 135 publications

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“…In suspensions of noninteracting hard spheres, this fluid-to-solid transition occurs when φ reaches the glass transition volume fraction, G 0.58 φ ≈ . At this concentration, particles are trapped in transient cages formed by their nearest neighbors and diffusion is no longer possible (see Quemada and Berli, 2002, for further discussions on this aspect). Similarly, the gelation of aggregating colloids has been suggested to occur when diffusing clusters become crowded .…”

Section: Aggregation and Gelationmentioning

confidence: 99%

“…The conceptual framework proposed in the recent literature clearly defines the role of particle concentration, interaction forces and shear stress in the aggregation and gelation of colloids (Trappe et al, 2001;Dawson, 2002;Bergenholtz et al, 2003). Relevant efforts have also been made to attain quantitative predictions of the rheometric functions in terms of colloidal interactions (see, for instance, Quemada and Berli, 2002). This knowledge is of primary importance in the food industry, where the physical properties of colloidal dispersions are generally controlled by adjusting the formulation.…”

Section: Introductionmentioning

confidence: 99%

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Rheology and phase behavior of aggregating emulsions related to droplet-droplet interactions

Berli

2007

Braz. J. Chem. Eng.

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-The present work deals with the relationship between colloidal interactions and physical properties of emulsions, in particular rheology and gel transition. Experimental data on protein-stabilized oil-in-water emulsions are considered. In this system, the excess of protein in the aqueous phase yields reversible droplet aggregation by the mechanism of depletion. Thus both phase and flow behaviors can be controlled by changing protein concentration, ionic strength and temperature. Calculations of the potential of interaction between droplets are carried out in the framework of colloid science. Particular emphasis is placed on the role that droplet-droplet interaction plays in defining the morphology of the aggregates, hence the microstructure and finally, the bulk physical properties. This understanding offers new perspectives in the study of complex food systems.

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Section: Aggregation and Gelationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rheology and phase behavior of aggregating emulsions related to droplet-droplet interactions

Berli

2007

Braz. J. Chem. Eng.

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“…The classical DLVO theory predicts the stability of the nanofluids by knowing the total energy of interaction between two particles [2,[16][17][18]. In the range of sizes of nanofluids, the ratio particle surface to particle volume is so high that all the interactions are controlled by short-range forces like Van der Waals attraction and surface forces.…”

Section: Introductionmentioning

confidence: 99%

“…In aqueous media, interparticle interactions at a given concentration can be changed by varying the ionic strength and the pH of the suspension [17,18].…”

Section: Introductionmentioning

confidence: 99%

Characterization of silica–water nanofluids dispersed with an ultrasound probe: A study of their physical properties and stability

et al. 2012

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of silica-water nanofluids dispersed with an ultrasound probe: A study of their physical properties and stability. Powder Technology, 2012, Vol. 224 AbstractThe stability and agglomeration state of nanofluids are key parameters for their use in different applications. Silica nanofluids were prepared by dispersing the nanoparticles in distilled water using an ultrasonic probe, which has proved to be the most effective system and gives the best results when compared with previous works. Results were obtained concerning the influence of the solid content, pH and salt concentration on the zeta potential, electrical double layer, viscosity, elastic and viscous moduli, particle size and light backscattering. Measurement of all these properties provides information about the colloidal state of nanofluids. The most important variable is the solid content.Despite the agglomeration due to high concentration, nanofluids with low viscosity and behaving like liquid were prepared at 20% of mass load thanks to the good dispersion achieved with the ultrasonic treatment. The pH of the medium can be used to control the stability, since the nanofluids are more stable under basic conditions far from the isoelectric point (IEP) and settle at pH = 2. Therefore, stable nanofluids for at least 48 h, with high solid content, can be prepared at high pH value (pH > 7) due to the electrostatic repulsion between particles.

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“…The transitions are detectable in plots of η r versus the reduced stress: (16.13) where σ C is the critical stress and D is the particle diameter. The non-Newtonian viscosity ratio depends on concentration and stress in the full range, σ = 0 −∞ [Quemada and Berli, 2002]: 16.14) where…”

Section: Model Suspension For Pncsmentioning

confidence: 99%